Bug 452360 - Enabling European wireless channels makes iwl4965 behave erratically
Enabling European wireless channels makes iwl4965 behave erratically
Status: CLOSED NOTABUG
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
8
All Linux
low Severity low
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Assigned To: John W. Linville
Fedora Extras Quality Assurance
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2008-06-21 08:01 EDT by James
Modified: 2008-06-25 14:11 EDT (History)
1 user (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
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Last Closed: 2008-06-25 14:11:03 EDT
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RHEL 7.3 requirements from Atomic Host:
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Attachments (Terms of Use)
dmesg output with ieee80211_regdom=64 option. (3.68 KB, text/plain)
2008-06-21 08:01 EDT, James
no flags Details
dmesg from kernel 2.6.25.8-35.fc8 using ieee80211_regdom="EU" (49.51 KB, text/plain)
2008-06-25 06:55 EDT, James
no flags Details

  None (edit)
Description James 2008-06-21 08:01:32 EDT
Description of problem:
Putting the line

    options cfg80211 ieee80211_regdom=64

in /etc/modprobe.conf to enable channels 12 and 13 (used by some APs in Europe)
results in erratic behaviour from iwl4965. The system becomes very sluggish
every few seconds.

Version-Release number of selected component (if applicable):
kernel-2.6.24.7-92.fc8
iwl4965-firmware-4.44.1.20-1

How reproducible:
Always.

Steps to Reproduce:
1. Ensure cfg80211 is loaded with ieee80211_regdom=64.
2. Reload iwl4965, iwlcore, mac80211 and cfg80211.

Actual results:
Very sluggish system, multiple ucode errors seen in dmesg (attached).

Expected results:
Euro channel access points detected and used.
Comment 1 James 2008-06-21 08:01:32 EDT
Created attachment 309965 [details]
dmesg output with ieee80211_regdom=64 option.
Comment 2 John W. Linville 2008-06-24 09:21:01 EDT
Hmmm...well, I think there is some confusion here.  The line in
/etc/modprobe.conf should either be

   options mac80211 ieee80211_regdom=64

for older kernels or it should be

   options cfg80211 ieee80211_regdom="JP"

for newer kernels.  In either case, the dmesg output in comment 1 looks more
like a driver/firmware interaction problem to me.  I would recommend changing 64
to "JP" and using a newer kernel:

   http://koji.fedoraproject.org/koji/buildinfo?buildID=52605

Does this improve things for you?
Comment 3 James 2008-06-25 06:53:48 EDT
OK, I didn't do *exactly* what you asked, I tried kernel-2.6.25.8-35.fc8 from
Koji and passed ieee80211_regdom="EU" (a guess, not wishing to upset the GPO
;)). This produced basically the same result from the desktop perspective:
sluggishness every few seconds. It also wouldn't associate. A dmesg is attached.

[Of course, if kernel-2.6.25.6-27.fc8 somehow contains newer code I'll gladly
try that version.]
Comment 4 James 2008-06-25 06:55:16 EDT
Created attachment 310251 [details]
dmesg from kernel 2.6.25.8-35.fc8 using ieee80211_regdom="EU"

Note that this includes a stack dump from when I tried suspend/resume (see bug
#437677).
Comment 5 James 2008-06-25 07:01:22 EDT
John, re Comment #2: I've done a quick search on the IWL Bugzilla and nothing
concrete on this has turned up. Do you want me to try enabling ucode debugging
and report it to them?
Comment 6 John W. Linville 2008-06-25 08:46:50 EDT
Currently only rawhide kernels have support for "EU", so you probably want to
try "JP" for now.  As for the ucode debugging, if you are willing to do that it
will probably be very helpful...thanks!
Comment 7 James 2008-06-25 14:11:03 EDT
OK, you were right... I tried kernel-2.6.25.9-37.fc8 with ieee80211_regdom="JP"
and it appeared to behave. So I've no idea what EU was doing... closing as NOTABUG.

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